The IRS uses automated systems to flag returns that look unusual compared to similar businesses. When your numbers fall outside normal ranges for your industry and income level, your return gets a second look.

Deductions that seem too high relative to your revenue are the most common trigger. If you report $150,000 in income and $140,000 in expenses while similar businesses average 60% expense ratios, your return stands out. The same applies to specific categories. Claiming $30,000 in travel expenses when your industry average is $5,000 raises questions.

Reporting losses year after year invites scrutiny. The IRS wants to determine whether you’re running a legitimate business or claiming hobby expenses as deductions. Three or more consecutive years of losses on a Schedule C often triggers review. This is especially common with businesses that have another income source covering living expenses.

Cash-heavy businesses face higher audit rates regardless of what they report. Restaurants, retail stores, and service businesses that handle significant cash have more opportunity for unreported income. The IRS knows this and applies more scrutiny to these industries as a result.

Large or unusual deductions for home offices, vehicle expenses, and meals draw attention. These categories are frequently abused, so the IRS watches them closely. A home office deduction that represents 40% of your home when you also rent office space looks suspicious. Vehicle deductions claiming 100% business use rarely hold up to examination.

Mixing personal and business expenses is one of the fastest ways to create audit risk. Using one credit card for both, paying personal bills from a business account, or failing to separate finances creates messy records that raise red flags. Professional services firms and other owner-operated businesses frequently make this mistake.

Inconsistencies between what you report and what third parties report will almost always trigger a notice. If your 1099s show $200,000 in payments received but you report $180,000 in revenue, the IRS will want to know why. Their matching systems catch these discrepancies automatically.

Round numbers throughout a return suggest estimation rather than actual recordkeeping. Expenses of exactly $5,000, $10,000, or $25,000 across multiple categories look like guesses. Real businesses have real numbers with cents attached.

The best protection against an audit is accurate books maintained throughout the year. Premium business accounting in Boca Raton with proper oversight means your returns reflect reality and you have documentation to support every number. When your financials are clean and your deductions are legitimate, an audit becomes an inconvenience rather than a crisis.

Keep records for at least seven years. Bank statements, receipts, invoices, and contracts should all be organized and accessible. If the IRS does come calling, having immediate access to supporting documentation usually resolves questions quickly.